bumblebee-status/modules/core/brightness.py

# pylint: disable=C0111,R0903

'''Displays the brightness of a display

Parameters:
    * brightness.step: The amount of increase/decrease on scroll in % (defaults to 2)
    * brightness.device_path: The device path (defaults to /sys/class/backlight/intel_backlight), can contain wildcards (in this case, the first matching path will be used)

'''

import bumblebee.util
import bumblebee.input
import bumblebee.output
import bumblebee.engine

import glob

class Module(bumblebee.engine.Module):
    def __init__(self, engine, config):
        super(Module, self).__init__(engine, config,
                                     bumblebee.output.Widget(full_text=self.brightness))
        self._brightness = 0

        self._device_path = self.find_device(self.parameter('device_path', '/sys/class/backlight/intel_backlight'))
        step = self.parameter('step', 2)

        if bumblebee.util.which('light'):
            self.register_cmd(engine, 'light -A {}%'.format(step),
                              'light -U {}%'.format(step))
        elif bumblebee.util.which('brightnessctl'):
            self.register_cmd(engine, 'brightnessctl s {}%+'.format(step),
                              'brightnessctl s {}%-'.format(step))
        else:
            self.register_cmd(engine, 'xbacklight +{}%'.format(step),
                              'xbacklight -{}%'.format(step))

    def find_device(self, device_path):
        res = glob.glob(device_path)
        if len(res) == 0:
            return device_path
        return res[0]

    def register_cmd(self, engine, upCmd, downCmd):
        engine.input.register_callback(self, button=bumblebee.input.WHEEL_UP, cmd=upCmd)
        engine.input.register_callback(self, button=bumblebee.input.WHEEL_DOWN, cmd=downCmd)

    def brightness(self, widget):
        if isinstance(self._brightness, float):
            return '{:3.0f}%'.format(self._brightness).strip()
        else:
            return 'n/a'

    def update(self, widgets):
        try:
            with open('{}/brightness'.format(self._device_path)) as f:
                backlight = int(f.readline())
            with open('{}/max_brightness'.format(self._device_path)) as f:
                max_brightness = int(f.readline())
                self._brightness = float(backlight * 100 / max_brightness)
        except:
            return 'Error'

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